Quadriceps tendon stripper

ABSTRACT

A cutting implement includes a V-shaped blade portion that defines an aperture through which a quadriceps tendon may pass as a doctor harvests the tendon through a minimally invasive procedure.

PRIORITY APPLICATION

The present application is a divisional of U.S. patent application Ser.No. 14/529,262 filed Oct. 31, 2014 ('262 application), issued as U.S.Pat. No. ______. The contents of the '262 application are hereinincorporated by reference in their entirety.

The '262 application is a divisional of U.S. patent application Ser. No.13/102,562 filed May 6, 2011 ('562 application), issued as U.S. Pat. No.8,894,672. The contents of the '562 application are herein incorporatedby reference in their entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to a cutting instrument adapted to help asurgeon harvest a replacement tendon for an anterior cruciate ligament(ACL) injury from the quadriceps tendon.

BACKGROUND

Most people can go through the majority of their life without evercaring or knowing how complicated a structure the knee that helps themwalk is. However, the knee remains a fragile mechanical structure thatis readily susceptible to damage. While medical advances have maderepairing the knee possible, repair of certain types of injuries resultsin other long term effects. To assist the reader in appreciating theelegance of the present disclosure, FIG. 1 is provided with a briefexplanation of the components of the knee.

For the purposes of the present disclosure, and as illustrated, the kneemay be composed of the quadriceps muscles 10, the femur 12, thearticular cartilage 14, the lateral condyle 16, the posterior cruciateligament 18, the anterior cruciate ligament 20, the lateral collateralligament 22, the fibula 24, the tibia 26, the patellar tendon 28, themeniscus 30, the medial collateral ligament 32, the patella 34 (shownslightly displaced to the side—it normally rests in the center of theknee) and the quadriceps tendon 36. Of particular interest for thepurposes of the present disclosure is the anterior cruciate ligament(ACL) 20 and what is done to repair the ACL 20.

ACL tears are common in athletes and are usually season ending injuries.The ACL 20 cannot heal—it must be surgically reconstructed. Thereconstruction requires replacement tissue. The most common tissue usedis a central slip of the patient's own patellar tendon 28. In practice,the patellar tendon 28 has proven to be generally effective, but thesize of the graft that can be used is limited to the size of thepatient's own patellar tendon 28. As a rule of thumb, only a third ofthe patellar tendon 28 may be harvested as a graft. Thus, a doctor willmeasure the width of the patellar tendon 28, divide by three, and takethe middle third of the patellar tendon 28. Such harvested grafts arerarely more than 10 mm wide and may be smaller. Taking this tissue froma person's patellar tendon 28 also causes significant pain anddiscomfort in the post operative healing period, which may last up to ayear, and up to twenty (20) percent of these patients are left withchronic anterior knee pain.

Some doctors recommend and use other graft sources, such as cadavergrafts, but cadaver grafts have a higher failure rate. Additionally,there is a non-zero chance of disease transmission or rejection by thepatient's immune system. As a final drawback, cadaver grafts are usuallyquite expensive and may not be covered by some insurance companies.

Other doctors use hamstring tendons (e.g., the distal semitendinosustendon) because the scar created during harvesting is relatively smalland there is less pain during the rehabilitation, but again, thehamstring tendon has its own collection of disadvantages. Thedisadvantages include the fact that once the graft is taken, a patient'shamstring will never recover to its previous strength. Further, allhamstring reconstructions stretch and are looser than the original ACL20. This loosening is particularly problematic in younger femaleathletes.

Another alternative graft source is the quadriceps tendon 36. Thequadriceps tendon 36 is larger and stronger than either the patellartendon 28 or the hamstring tendon. The quadriceps tendon 36 is likewisestiffer and less prone to stretching or plastic deformation. However,the qualities that make the quadriceps tendon 36 attractive alsocontribute to the difficulty in harvesting a graft from the quadricepstendon 36. Existing surgical implements require a large incision up thelongitudinal axis of the femur 12 on the front of the thigh to cut downto the level of the tendon 36, resulting in a large post operative scar.Additionally, the quadriceps tendon 36 has a consistency similar to theproverbial shoe leather, making it difficult to cut. However, an ACL 20repaired with grafts from the quadriceps tendon 36 generally result inalmost no anterior knee pain postoperatively over the short or long termand recover quicker. The difficulties in harvesting a quadriceps tendon36 led to the present disclosure's exploration of an alternate modalityfor harvesting a graft from the quadriceps tendon 36.

SUMMARY

The present disclosure provides a cutting implement that is adapted toharvest a graft from the quadriceps tendon in a minimally invasivemanner. Once the quadriceps tendon graft is secured, it may be used inconventional manners to repair the anterior cruciate ligament (ACL). Thecutting implement comprises a handle portion and a blade portion. Theblade portion comprises a V-shaped cutting surface that is angled up andaway from a distal point of the cutting surface. The space between thearms of the V is open allowing the harvested graft to pass therethrough.A top element spans the distance between the tops of the arms of the Vand helps isolate the quadriceps tendon from tissue that is positionedsuperiorly relative to the tendon.

In alternate embodiments, the top portion may comprise a cutting surfaceas well or the cutting implement may include a secondary cutting elementthat is adapted to cut the far end of the quadriceps tendon when a graftof a suitable length has been harvested. In still another embodiment, anauxiliary cutting device may be used to clip the far end of the tendononce the appropriate length has been stripped. The auxiliary cuttingdevice may be a blade, scissors, or an electrocautery device inparticularly contemplated embodiments. In another alternate but notmutually exclusive embodiment, the cutting surface of the V-shapedcutting surface is serrated.

In another non-exclusive, alternate embodiment, spacers may be used toadjust the dimension of the cut. The spacers may be a polymeric materialand placed between the tendon and the top element, effectively raisingthe top element away from the tendon, and thus narrowing the width ofthe V-shape cutting edge that is cutting the tendon.

In another embodiment, a second blade may be used that may fit insidethe main blade. The second blade may move independently, reciprocatingrelative to the main blade so that the two blades operate like ascissor.

Those skilled in the art will appreciate the scope of the disclosure andrealize additional aspects thereof after reading the following detaileddescription in association with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thisspecification illustrate several aspects of the disclosure, and togetherwith the description serve to explain the principles of the disclosure.

FIG. 1 illustrates a conventional knee;

FIG. 2 illustrates a perspective view of an exemplary embodiment of thecutting implement of the present disclosure;

FIG. 3 illustrates a side elevational view of an exemplary embodiment ofthe cutting implement of the present disclosure;

FIG. 4 illustrates a front elevational view of the cutting implement ofFIG. 3;

FIG. 5 illustrates a back elevational view of the cutting implement ofFIG. 3;

FIG. 6 illustrates a top plan view of the cutting implement of FIG. 3;

FIG. 7 illustrates a knee with a bone graft guide positioned thereon asis done at the beginning of tendon harvesting;

FIGS. 8 and 9 illustrate the bone graft guide positioned on the patellaas is used to form the bone graft;

FIG. 10 illustrates the cutting implement beginning to cut thequadriceps tendon;

FIG. 11 illustrates the cutting implement with a portion of theharvested graft extending from the back end of the cutting implement;

FIG. 12 illustrates an alternate embodiment with a serrated blade;

FIG. 13 illustrates another alternate embodiment with a distinct andselectively extendable distal cutting element;

FIG. 14 illustrates a flow chart setting forth the method of using thecutting implement of the present disclosure;

FIG. 15 illustrates spacers that may be used to control the width of thecut.

FIGS. 16A and 16B illustrate an embodiment with a scissor type cuttingelement; and

FIG. 17 illustrates an electrocautery tip auxiliary cutting element.

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the disclosure andillustrate the best mode of practicing the disclosure. Upon reading thefollowing description in light of the accompanying drawings, thoseskilled in the art will understand the concepts of the disclosure andwill recognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure and the accompanying claims.

FIGS. 2-6 illustrate a first exemplary embodiment of a cutting implement50 according to the present disclosure. The cutting implement 50includes a handle portion 52 and a blade portion 54. Collectively, thehandle portion 52 and blade portion 54 may have a longitudinal length ofabout ten inches (25.4 cm). The handle portion 52 may include indicia 56disposed thereon that provide a measurement tool whose use will beexplained in greater detail below. The handle portion 52 may be knurled(not shown), have finger indentations (not shown), or have otherfeatures to facilitate grasping of the handle portion 52, even duringsurgery when blood and other bodily fluids might otherwise make thehandle portion 52 slippery.

The blade portion 54 includes a first cutting surface 58 and a secondcutting surface 60 joined to form a V-shape, with a point 62 and a wideportion 64. The two sides that form the cutting surfaces together definean aperture 66 that extends along the longitudinal axis of the cuttingimplement 50. The aperture 66 is closed on the top by a top portion 68that extends across the wide portion 64 of the V-shape. The top portion68 may include a cutting surface 70 that allows the cutting implement 50to pass through tissue more readily. Manufacturing constraints mayrequire the point 62 to be a tight curved tip instead of a true point,and as used herein “point” includes both a true point and such curvedpoints.

As better seen in FIGS. 3 and 6, the top portion 68 extends over atleast a portion of the cutting surfaces 58, 60. Likewise, as better seenin FIG. 3, the cutting surfaces 58, 60 slant up and back from the point62.

In an exemplary embodiment, at least the blade portion 54 is made ofsurgical grade steel and the cutting surfaces 58, 60 are honed to a highdegree of sharpness comparable to that of a conventional scalpel.Alternatively, the cutting surfaces 58, 60 could be a synthetic diamondscalpel blade having a cutting width of approximately 3 nm or some formof cracked glass (e.g., obsidian), which may have cutting edges on theorder of 200 Angstroms. Exemplary diamond scalpels are sold by CliniconCorporation of Oceanside Calif. Exemplary obsidian scalpels are sold byFine Science Tools of Foster City Calif.

The cutting implement 50 may be part of a kit that includes the cuttingimplement 50, a cutting guide 72 (FIGS. 7-9), and a spacer 74 (FIG. 15).Additionally, the kit may include an auxiliary cutting element such apair of scissors or an electrocautery cutting element as described ingreater detail below. This kit may be made as a single use kit, or theelements of the kit may support multiple sterilizations in an autoclaveor comparable sterilization environment.

The cutting guide 72 is illustrated in use in FIGS. 7-9. The cuttingguide may be generally trapezoidally shaped body 76 (FIG. 9) andincludes an optional handle 74 and posts 78. The bottom surface 80 ofthe body 76 may be about eleven (11) mm across, although otherdimensions are also possible. In an exemplary embodiment, the width ofthe bottom surface is slightly smaller than the width of the wideportion 64 of the blade portion 54 of the cutting implement 50.Furthermore, the sidewalls 82 are slanted such that if the sidewalls 82were extended past the bottom surface 80, an equilateral triangle 84 isformed. In use, a chisel or other cutting implement is placed next tothe guide 72 and used to cut into the patella 34. The cuts made in thisfashion cut an equilateral triangle bone plug 86 (FIG. 11) that fitswithin the aperture 66 of the cutting implement 50.

Once the bone plug 86 has been cut, the guide 72 is removed, andsurgical thread is threaded into the holes for the posts 78, the threadis then pulled up, effectively fishing the bone plug 86 out of thepatella 34. When selecting the place from which to create the bone plug86, at least a portion of the bone plug 86 should be attached to thequadriceps tendon 36. Thus, when the bone plug 86 is extracted from thepatella 34, it is still attached to the quadriceps tendon 36. The boneplug 86 is then fed into the aperture 66 and the cutting implement isready to begin cutting (see FIG. 10). The cutting implement 50 is thenpushed anteriorly up the longitudinal axis of the femur 12, beneath theskin of the patient. The sharp cutting surfaces 58, 60 cut through thetough quadriceps tendon 36. The doctor may compare the length ofharvested tendon 88 (FIG. 11) to the indicia 56 to see if the doctor hasharvested or stripped enough tendon 36.

FIG. 12 illustrates an alternate embodiment wherein the cutting surfaces58 a, 60 a are serrated. In some situations, the serrations may make iteasier to cut the tough tendon 36.

FIG. 13 illustrates another alternate embodiment, wherein a selectivelyextendable blade 90 is positioned on the top surface 68. The extendableblade 90 may be used to sever the far end of the tendon 36 once anacceptable length of tendon has been harvested. In a first, retractedposition the blade 90 may be positioned within a sheath. In a second,extended position, the blade 90 may be exposed and extend past the frontof the top surface 68 such that the blade is approximately as farforward as the distal point 62.

FIG. 15 illustrates a spacer 92, which in an exemplary embodimentcomprises a polymeric washer shape approximately 1 mm thick. The spacer92 may be positioned underneath the top surface 68 on the tendon 36.Because the aperture 66 is an equilateral triangle, each spacer 92effectively lifts the cutting surfaces 58, 60 an equal distance andeffectively narrows the amount of tendon 36 that is harvested. Forexample, if the wide portion 66 is eleven mm wide, one spacer 92 wouldlift the blades one mm, causing the widest cutting part to now be tenmm. Additional spacers 92 may be stacked to reduce the width of theharvesting further as needed.

FIGS. 16A and 16B illustrate another alternate embodiment wherein thecutting implement 50A has a scissor-like cutting portion 54A. Asillustrated, the cutting portion 54 a includes primary cutting surfaces58A, 60A and reciprocating V-shaped cutting surface 94 that movesrelative to the primary cutting surfaces 58A, 60A. In a firstembodiment, the cutting surface 94 moves up and down in a generallyarcuate motion (generally indicated at 96), and the cutting effect isachieved as the blades close, similar to conventional scissors. In asecond embodiment, the cutting surface 94 moves along the longitudinalaxis of the cutting implement 50A (generally indicated at 98) so thatthe cutting surface 94 moves in and out of the aperture 66.

FIG. 17 illustrates an auxiliary cutting element 150 that is used tosever the distal end of the quadriceps tendon 36. The auxiliary cuttingelement 150 may be an electrocautery element shaped like a cylinder 152with a short axis 154 and an insulated, rotating cautery tip 156selectively extendable at a distal end of the element 150. In practice,the cutting element 50 is used to strip a section of the tendon 36. Thenthe cutting element 50 is withdrawn, and the bone plug 86 and theharvested tendon 88 are fed through the cylinder 152 of the auxiliarycutting element 150. The cautery tip 156 is then simultaneouslyextended, rotated, and heated (or heated and extended and rotated). Thecautery tip 156 rotates inwardly towards the center of the cylinder 152.The auxiliary cutting element 150 is rotated about the harvested tendon88, moving the extended cautery tip 156 through the distal end of theharvested tendon 88. This movement effectively cuts the tendon 88 at thefar point and is believed to be less invasive than simply advancing thecutting implement 50 to the end of the tendon 36 and into the muscle(which would effectively “tear” the harvested tendon 88 from theattached fibers and the quadriceps). Cautery elements are known and canbe adapted from those sold by websites such aswww.dremed.com/catalog/product_info.php/cPath/45_78/products_id/421 andwww.orsupply.com/medical/category/Cautery+Electrodes/489.

In another embodiment, not specifically illustrated, a cutting implementcould take the form of a pair of scissors such as a modified pair ofOB-GYN scissors. In particular, the scissors may be modified so that thehinge is more in the middle of the scissor than is typical. By movingthe hinge, the scissors can be used deep in the wound, keeping theincision small. Still other cutting implements could be used to severthe distal end of the harvested tendon 88 as desired.

FIG. 14 illustrates a flow chart explaining use of the cutting implement50. The doctor makes an initial incision at a knee fold line (block100), such as an anterior fold line, and folds the skin back to expose aportion of the patella 34. The doctor drills two post holes into thepatella 34 proximate the quadriceps tendon 36 (block 102). The holes maybe approximately eleven mm deep in an exemplary embodiment. The doctorthen places the guide 74 on the patella 34, with the posts 78 positionedwithin the holes (block 104). The doctor will chose the width of thequadriceps tendon to be harvested by measuring the size of thequadriceps tendon preoperatively from MRI imaging and comparing them tothe intraoperative observations of the tendon itself. Cross sectionalarea of the patellar tendon can be calculated from the MRI, and onethird this patellar tendon area can be compared to the cross sectionalareas resulting from different quadriceps options based on the areas ofthe equilateral triangles resulting.

Next the bone plug 86 is created by cutting into the patella 34 usingthe sidewalls of the guide 74 to guide the cuts into the patella 34,thereby creating the equilateral bone plug 86 and the initial cut intothe quadriceps tendon 36 (block 106). The guide 74 directs the saw bladesuch that the resulting bone plug 86 is of the same dimensions as thequadriceps graft that has been chosen, allowing it to be slipped throughthe aperture 66 on the blade portion 54 (block 108). The graft may besecured by sutures based through the original holes drilled at thebeginning of the procedure, facilitating passage of the bone plug 86. Ifnecessary, the doctor inserts one or more spacers 92 to space the topsurface 68 from the tendon 36, narrowing the cutting width. The doctorthen slices anteriorly up the quadriceps tendon 36 underneath the skinof the patient (block 110). When an appropriate length of tendon 36 hasbeen cut, the doctor severs the distal end of the tendon 36, such as byrotating the top portion 68 into contact with the tendon 36 and sawing,or selectively extending the extendable blade 90 and using it to sawthrough the tendon 36. Alternatively, a second blade may be insertedthrough the incision and used to cut the distal end of the tendon 36. Asstill another option, the doctor may insert the auxiliary cuttingimplement 150, extend the cautery tip 156 and cauterize the end of thetendon 36. Still another option is to make a new incision further up thethigh proximate the distal end and make a cut into the tendon 36 at thesecond incision. The doctor then removes the tendon (block 114) andcloses the incision (block 116).

Those skilled in the art will recognize improvements and modificationsto the embodiments of the present disclosure. All such improvements andmodifications are considered within the scope of the concepts disclosedherein and the claims that follow.

What is claimed is:
 1. A surgical instrument comprising: a handleportion; and a blade portion joined to the handle portion, the bladeportion comprising: a first cutting surface; a second cutting surfacejoined to the first cutting surface to form a V-shape having a point anda wide portion, the first and second cutting surfaces defining anaperture extending through the blade portion, wherein the first andsecond cutting surfaces are configured to cut a quadriceps tendon and inso doing, pass a cut portion of the quadriceps tendon through theaperture; wherein the first and second cutting surfaces are arrangedsuch that the first and second cutting surfaces slant up and back fromthe point; and a top portion extending across the wide portion of theV-shape, the top portion comprising: a handle side proximate the handleportion, a front edge opposite the handle side, and the point of theblade portion extends away from the handle portion past the front edgeof the top portion.
 2. The surgical instrument of claim 1, wherein theblade portion comprises a steel blade portion.
 3. The surgicalinstrument of claim 1, wherein the first and second cutting surfacescomprise serrated cutting surfaces.
 4. The surgical instrument of claim1, further comprising a spacer selectively positionable beneath the topportion to space the top portion from a work piece being cut by thefirst and second cutting surfaces.
 5. The surgical instrument of claim1, wherein the top portion does not include a cutting surface.
 6. Asurgical kit, comprising: a spacer; a guide configured to assist asurgeon in creating a bone plug extract from a patella; and the surgicalinstrument of claim 1.